The use of air ionizers has become increasingly popular in recent years, as people look for ways to improve the air quality in their homes and workplaces. But what are the health effects of breathing ionized air? Some critics believe that air ionizers emit dangerous levels of ozone, which can be hazardous to health when inhaled in high enough doses. Ozone, a lung irritant, is produced indirectly by ion generators and some other electronic air purifiers and directly by ozone generators. There is no difference between the ozone present in outdoor smog and the ozone produced by these devices.
Under certain conditions of use, ion generators and other ozone-generating air filters can produce levels of this lung irritant well above levels considered harmful to human health. While ozone can be used to reduce odors and pollutants in unoccupied spaces, the levels needed to achieve this are above what is generally considered safe for humans. People who buy ozone generators may not know that ozone can damage cells in the lungs and respiratory tract. Exposure to ozone irritates and inflames the lining of the respiratory system, causing symptoms such as coughing, chest tightness, shortness of breath, and difficulty breathing.
Ozone can worsen asthma symptoms and may contribute to the development of asthma. High exposures to ozone can cause permanent lung damage, and repeated exposure can even increase the risk of death among people who already have health problems. People who are particularly vulnerable to health problems caused by ozone inhalation include children and people who already have asthma or other respiratory diseases, including the elderly. There are many experimental studies on animals that show the respiratory effects of ozone exposure. Birds are especially sensitive to the effects of air pollutants, including ozone. One of the most popular types of air purifiers on the market right now are ion generating systems, including “bipolar ionization” devices that electrically charge particles so that they are deposited in the air faster and are typically marketed to kill bacteria, fungi, and viruses.
Another recent study on air ionizers in school classrooms reduced particulate matter concentrations and led to some improvements in the respiratory health of children ages 11 to 14. However, ionizers had an adverse effect on heart rate variability (a measure of cardiovascular health), meaning that any benefit to the lungs came at a cost to the heart. In their 6-month study, the authors found no statistically significant difference in PEFR (peak expiratory flow rate) between active ionization and placebo or non-ionizer environments. A wide range of respiratory measures, including respiratory rate, multiple measures of lung function, and respiratory symptoms, were studied after exposure to ionized air particles. Air purifiers that use electrostatic ionizers and precipitators are other types of devices that emit ozone, but they do so as a by-product of their design and function. Unlike air filtration (in which air is passed through a filter to remove pollutants from the air), very little research has been done on the efficacy and side effects of “additive cleaning” air methods, such as ionizing devices. Zylberberg and Loveless conducted a controlled double-blind study on 16 asthmatic men and women (15 to 5 years old) during two periods of exposure of 120 minutes to ionized air. There were no appreciable effects on lung function at rest and the effect of ionized air on the sensitivity of inhaled histamine was equivocal. The health effects of air ionizers are largely unknown, although a small number of recent studies are cause for concern.
In addition, they examined whether negative air ion therapy was beneficial to the growth and development of five infants, and found that the infants' weight gain, heart rate, and body temperature did not change significantly when exposed for 2 hours during a 2-week ionization period compared to periods of non-ionization. The study found comparable changes between positive and negative exposure to air ions despite the concentration level used, and no notable metabolic alterations attributable to ionization were identified. In addition, air ions are produced by air-ionizing devices sold to clean indoor air from aerosols and particles through electrostatic precipitation; they are also produced by corona activity on the surface of the high-voltage transmission conductors of the alternating current (AC) and direct current (DC) transmission lines. Overall, it is clear that more research needs to be done on the health effects of breathing ionized air before any definitive conclusions can be made about its safety or efficacy. In the meantime, it is important for people who use these devices to be aware that there may be potential risks associated with their use.
